BikeMaster Maintenance Free Battery - BTX20L-BS BTX20L-BS Maintenance Free Comes with pre-measured acid tubes that dealer easily empties into battery. Includes a seal that is then placed across top of battery to create a sealed, spill-proof battery. 1-year manufacturers warranty. Once activated, requires charging during prolonged storage periods. Yuasa Reference: YTX20L-BS / 12N16-3B